One of the most common questions regarding snails is how to make sure they get the calcium they need to grow and maintain their shells. One way to do that is by providing them with calcium-rich foods to eat. Here is a list of vegetables and fruits that have significant amounts of calcium.

Vegetables Calcium per 100 gram
Dill Weed 208 mg
Turnip Greens 190 mg
Collards 145 mg
Parsley 138 mg
Kale 135 mg
Watercress 120 mg
Beet Greens 119 mg
Chinese Cabbage 105 mg
Mustard Greens 103 mg
Chicory Greens 100 mg
Spinach 99 mg
Okra 81 mg
Leaf Lettuce 68 mg
Cilantro 67 mg
Purslane 65 mg
Endive 52 mg
Swiss Chard 51 mg
Broccoli 48 mg
Cabbage 47 mg
Rutabaga 47 mg
Brussel Sprouts 42 mg
Celery 40 mg
Sweet Potato Leaves 37 mg
Green Beans 37 mg
Romaine Lettuce 36 mg
Parsnips 36 mg
Head Lettuce 32 mg
Alfalfa Sprouts 32 mg
Squash (winter, all varieties) 31 mg
Turnip 30 mg
Carrots 27 mg
Kohlrabi 24 mg
Sweet Potato 22 mg
Cauliflower 22 mg
Asparagus 21 mg
Pumpkin 21 mg
Squash (summer, all varieties) 20 mg
Beets 16 mg
Cucumber (with skin) 14 mg
Red and Green Peppers 9 mg
Tomato 5 mg
White Corn 2 mg

Fruits Calcium per 100 gram
Seedless Raisins 49 mg
Orange 40 mg
Lime 33 mg
Blackberries 32 mg
Kiwi 26 mg
Lemon (no peel) 26 mg
Papaya 24 mg
Raspberries 22 mg
Sweet Cherries 15 mg
Strawberries 14 mg
Tangerine 14 mg
Apricots 14 mg
Grapefruit, White 12 mg
Grapefruit, Red & Pink 11 mg
Pear 11 mg
Cantaloupe 11 mg
Grapes 11 mg
Mango 10 mg
Watermelon 8 mg
Persimmon, Japanese 8 mg
Pineapple 7 mg
Apple (with skin) 7 mg
Cranberries 7 mg
Banana 6 mg
Honeydew Melon 6 mg
Blueberries 6 mg
Casaba Melon 5 mg
Nectarine 5 mg
Peach 5 mg
Plum 4 mg

Thanks to Scrup for finding and first posting this list.